After finally debuting, Mario Kart 8 on the Wii U was trending online after silly videos of Luigi giving a serious stare hit the Web. That inspired The Fine Brothers to show their group of kids the video to see how they react to Mario’s angry brother. 

Read more: http://www.viralviralvideos.com/2014/06/24/kids-react-to-luigi-in-mario-kart-8/